The European Consumer Centre recently dealt with a woman who rented a car for a weekend break. On return, she left it at a drop-off point, as requested. A couple of weeks later she received a letter from the car rental company saying that they were debiting her credit card £113 because of damage to the bumper. She denies any damage was done.
The centre suggests that car-rental customers make sure there will be someone at the drop-off point to verify that the car is undamaged on return.